Hitherto, a coil wound around a stator or a rotor of a rotary electric machine passes through in line in slots that are holding portions for the coil. More particularly, there are disclosed a coil whose coil conductor cross-section is formed in a rectangular shape or a trapezoidal shape along the shape of the slot and a coil whose coil conductor shape is formed in a trapezoidal shape that is different depending on a slot insertion position. Furthermore, one side and the other side of the coil conductor are formed in parallel planes. (Refer to FIG. 12 of Patent Document 1.)
Moreover, in a conventional method of manufacturing a coil, there is disclosed one in which at least a portion of a coil to be inserted into a slot is inserted and arranged in a forming die having a previously determined trapezoidal shaped groove and a coil conductor is pressed by a pressing die to be formed in a trapezoidal shape. Furthermore, one side and the other side of the coil conductor are formed in parallel planes. (Refer to Patent Document 2.)